Centrifugal pump assembly

ABSTRACT

A fluid delivery system, particularly suitable for vehicles for pumping water from a supply tank, and including a centrifugal pump and a motor for driving same. A pressure and flow sensitive control device associated with the water as discharged from the pump controls a switch which activates the motor, whereby the motor and pump are energized and de-energized in response to the movements of the control device, which control device in turn is moved in response to the external demand for water. The pump housing has a removable end cover which is secured to the housing by resilient releasable clips, which clips permit the end cover to be partially or totally released from the housing when a predetermined force is developed internally of the housing, such as caused by freezing of the water within the housing. A control plate is disposed closely adjacent the discharge side of the rotor for preventing the pressurized fluid from intimately contacting and applying a large axially directed force to the rotor, thereby effectively isolating the pressurized discharged fluid from the rotor to thus minimize rotor wear.

United States Patent 1 East my 3,819,297 451 June 25, 1974 [5 CENTRIFUGAL PUMP ASSEMBLY [75] Inventor: Robert East, Kalamazoo, Mich.

[73] Assignee: General Gas Light Company,

Kalamazoo, Mich.

221 Filed: Sept.l1, 1972 [21 Appl. No; 287,747

Primary ExaminerWilliam L. Freeh Attorney, Agent, or Firm-Woodhams, Blanchard and Flynn [57 1 ABSTRACT A fluid delivery system, particularly suitable for vehicles for pumping water from a supply tank, and including a centrifugal pump and'a motor for driving same. A pressure and flow sensitive control device associated with the water as discharged from the pump controls a switch which activates the motor, whereby the motor and pump are energized and de-energized in response to the movements of the control device, which control device in turn is moved in response to the external demand for water. The pump housing has a removable end cover which is secured to the housing 1 by resilient releasable clips, which clips permit the end cover to be partially or totally released from the housing when a predetermined force is developed internally of the housing, such as caused by freezing of the water within the housing. A control plate is disposed closely adjacent the discharge side of the rotor for preventing the pressurized fluid from intimately contacting and applying a large axially directed force to the rotor, thereby effectively isolating the pressurized discharged fluid from the rotor to thus minimize rotor wear.

9 Claims, 8. Drawing Figures 1 CENTRIFUGAL PUMP ASSEMBLY FIELD OF THE INVENTION This invention relates to a fluid delivery system and, in particular, to a system incorporating a motor and a centrifugal pump and having means associated therewith for minimizing wear of the rotor due to the pressurized fluid, and for preventing damage to the pump due to creation of excessively large forces within the pump, such as caused by freezing of the pumped liquid.

BACKGROUND OF THE INVENTION Vehicles such as mobile homes, campers and the like are generally provided with a self-contained water system for permitting water to be supplied as needed to various devices, such as a water heater, faucets and the like. These systems generally include a self-contained tank for permitting storage of a substantial quantity of water, which tank is connected to a motor-pump combination for permitting the water to be withdrawn from the tank and supplied to a suitable discharge point. These self-contained fluid distribution systems for use on vehicles must be compact, economical to manufacture and operate, of relatively light weight, and substantially maintenance free.

In order to provide a fluid distribution system having the above characteristics, it has been general practice to utilize a centrifugal pump, and one such system of this type is illustrated in my prior US. Pat. No. Re. 26 678. Further, insystems of this type, it is desirable to construct the pump rotor or impeller from a relatively lightweight material, such as from nylon, plastic or the like. However, it has been discovered that when the rotors are constructed of materials of this type, the pressure of the fluid discharged by the rotor, which pressur ized fluid normally contacts the rotor over at least one axial face thereof, results in imposition of a large axial force on the rotor. This causes the rotor to be urged against a bearing member, whereby the rotor is thus subject to substantial and excessive wear during operation thereof. This excessive wear is extremely damaging to the rotor and substantially shortens the useful life thereof so that the rotor must'be replaced at routine in tervals to insure continued pump operation in the most efficient and desirable manner.

Another problem which has been experienced with great frequency within self-contained fluid systems, particularly systems mounted on vehicles, has been the damage caused by the freezing of the pumped fluid, particularly water, contained within the pump. Many persons, through oversight, forget to properly drain the pump prior to the onset of winter weather. Since most vehicles are not stored within protected or heated places, the exposure of the vehicle and the selfcontained fluid system mounted thereon to freezing temperatures results in the water within the system freezing. The freezing of the water within the pump, due to the substantial expansion which accompanies the freezing, generally causes serious damage to the pump, such as by causing breakage or deformation of the rotor structure. This thus requires either a replacement or a major repair of the pump prior to permitting further usage of same. This is, needless to say, undesirable since it results in the fluid system being disabled for a substantial period of time, and can result in costly maintenance and/or replacement.

Thus, the present invention relates to an improved liquid supply system, particularly for vehicles, which includes a centrifugal pump having suitable structure associated therewith for overcoming the abovementioned problems. Thus, the principal objects of this invention are:

1. To provide a liquid supply system, particularly for recreational vehicles such as mobile homes and campers, which utilizes a centrifugal pump having suitable housing structure which permits at least a portion of the housing to automatically release on development of a predetermined internal force or pressure within the pump chamber, such as caused by freezing of the liquid within the pump chamber.

2. To provide a liquid supply system, as aforesaid, wherein the'pump housing includes an end cover which is r eleasably secured to the main housing by resilient clips which automatically disengage to permit the end cover to be partially or totally disconnected from the housing upon the freezing of the liquid within the pump chamber.

3. To provide a liquid supply system, as aforesaid, wherein a control plane is disposed within the pump housing in close proximity to the axial end face of the pump rotor for substantially isolating the discharged pressure fluid from the rotor to prevent the discharged pressurized fluid from imposing undesirable axially directed forces on the rotor.

4. To provide a liquid supply system, as aforesaid, wherein the pump housing includes a pair of spaced wall members positioned closely adjacent the rotor and disposed on opposite sides thereof so that the pressurized fluid discharged from the rotor is isolated from the rotor and is supplied to a chamber permitting the fluid to be discharged to an external location.

5. To provide a liquid supply system, as aforesaid, which includes a sensitive control system capable of starting the pump upon creation of a demand for liquid, particularly water, and keeping the pump running at relative low demand rates, while still being capable of automatically shutting off the pump upon elimination of the demand for water.

6. To provide a liquid supply system, as aforesaid, wherein the control system can be adjusted to permit the flow and pressure sensitive control device to be responsive to a preselected pressure for controlling flow of liquid from the pump, with the preselected pressure being selectively variable over a relatively wide range.

Other objects and purposes of the invention will be apparent to persons acquainted with devices of this type upon reading the following specification and inspecting the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view, taken partially in cross section, of a motor-pump combination having a flow sensing control device associated therewith, same being constructed according to the present invention.

FIG. 2 is an end view of the structure illustrated in FIG. 1, same being taken from the right side of FIG. 1.

FIG. 3 is a further end view of the structure illustrated in FIG. 1, same being taken from the left side of FIG. 1.

FIG. 4 is an enlarged, fragmentary, sectional view of a portion of the pump structure illustrated in FIG. 1.

FIG. 5 is a fragmentary, sectional view taken along the line V-V in FIG. 4.

FIG. 6 is a fragmentary view taken substantially along the line VIVI in FIG. 2.

FIG. 7 is a fragmentary, sectional view taken substantially along the line VII-VII in FIG. 1.

FIG. 8 is a view, taken partially in cross section, of a discharge nozzle which can be utilized directly on the pump illustrated in FIG. 1 if desired.

Certain terminology will be used in the following description for convenience in reference only and will not be limiting. For example, the words rightwarly, leftwardly, upwardly and downwardly will designate directions in the drawings to which reference is made. The words forwardly and rearwardly will refer to directions of fluid flow through the device, forwardly being the normal flow direction. The words inwardly and outwardly will refer to directions toward and away from, respectively, the geometric center of the device and designated parts thereof. Said terminology will include the words above specifically mentioned, derivatives thereof, and words of similar import.

SUMMARY OF THE INVENTION In general, the objects and purposes of the present invention are met by providing a liquid supply system including a centrifugal pump driven by a motor and adapted for supplying liquid, particularly water, to an external discharge point. The system is specifically designed for use on vehicles of the mobile home type and is preferably provided with a water storage tank connected to the inlet side of the pump. A control device is associated with the discharge side of the pump for automatically energizing and de-energizing the motor in response to the external demand for water. A housing surrounds the pump rotor and includes an end cover, attached to the remainder of the housing by releasable clips for permitting the end cover to be partially or totally disconnected when a relatively high pressure exists within the pump chamber, such as caused by freezing of the water within the pump chamber. The pump also has a control plate positioned closely adjacent the rotor for preventing the pressurized water discharged from the rotor from exerting an axial pressure force on the rotor to thus minimize rotor wear, particularly when the rotor is constructed of plastic or the like. Other objects and purposes of the invention will be evident upon reading the following detailed description.

DETAILED DESCRIPTION The present invention relates to a liquid supply system which includes a centrifugal pump 11 connected to and driven by a conventional electric motor 12. A liquid, such as water, is supplied to the inlet side of the pump 11 from a storage system, such as a tank 13. The water discharged from the pump is then supplied to a suitable delivery pipe or conduit 14, which pipe has a valve 16 associated therewith for controlling the flow through the pipe 14. The pipe 14 may be connected to any conventional device, such as a hot water heater or a faucet, and the valve 16 may thus comprise either a manually actuated valve associated with a faucet or alternately it may comprise an automatically controlled valve associated with a hot water heater. The fluid as discharged from the pump 12 also flows through a control device 17 which is connected between the delivery pipe 14 and the discharge side of the pump for causing the motor 12 to be automatically energized or deenergized in response to the external demand for water, as controlled by the valve 16.

The pump 11 and motor 12 are, in the illustrated embodiment, mounted on an L-shaped mounting bracket 21 which includes a horizontal leg 22 adapted to be fixedly secured in a conventional manner to a suitable support surface. The mounting bracket also has a vertical leg 23 provided with suitable openings therein, through which openings extend suitable mounting studs as provided on the motor for permitting the motor to be secured to the vertical leg 23, which mounting studs receive thereon suitable threaded nuts 24. The motor 12 also has a motor shaft 26 extending therefrom and through a suitable opening formed in the vertical leg 23 for permitting the motor shaft to extend into the interior of the pump 11.

The pump 11 includes a substantially cup-shaped housing 27 having an annular sidewall 28 fixedly, here integrally, connected to a base wall 29 which is disposed in engagement with the vertical leg 23 and is fixedly secured thereto by being clamped between the vertical leg 23 and the nuts 24. The base wall 29 of the housing 27 has a conical portion 31 formed in the center thereof which extends inwardly into surrounding relationship with the motor shaft 26 and confines a resilient seal ring 32 disposed in sealing engagement with the motor shaft 26. An intermediate platelike partition 33 is disposed within the cup-shaped housing 27 and includes a conical portion 34 disposed in surrounding relationship to the motor shaft 26 and having its inner edge positioned adjacent the inner edge of the conical portion 31. The conical partition portion 34 extends radially outwardly and is fixedly, here integrally, connected to an annular sidewall portion 36 which is disposed in engagement with the sidewall portion 28 of the cup-shaped housing 27. The partition 33 has an annular flange 37 extending radially outwardly from the outer axial end of the sidewall portion 36, which radial flange 37 is axially spaced from a hooklike radial flange 38 fonned on the free edge of the cup-shaped housing 27. The flanges 37 and 38 are axially spaced and confine therebetween an annular resilient seal ring 39.

An annular sleeve member 41 is disposed within the housing 27 and extends axially between the conical wall portions 31 and 34, resulting in the formation of an annular liquid supply chamber 42 therebetween. An inlet conduit 43 is connected to the pump housing 27 and communicates with the supply chamber 42, which inlet supply conduit 43 is adapted to be connected to an intermediate delivery conduit for permitting the inlet of the pump to be connected to the liquid supply tank 13 as illustrated in FIG. 2.

The pump housing 27 is normally closed by means of a releasable end cover 44 which is releasably secured to the free edge of the cup-shaped housing 27 and is disposed in axially spaced relationship to the conical portion 34 of the partition 33, thereby resulting in the formation of a chamber therebetween in which is positioned a conventional pump rotor or impeller 46. The rotor 46 has a center hub portion 47 which is nonrotatably mounted on the motor shaft 26. The rotor further has a plurality of circumferentially spaced flow passages 48 formed therein, with each flow passageway 48 including an axial passage 49 formed adjacent the hub 47 and communicating atits rearward end with the fluid supply chamber 42 through a plurality of openings 51 formed in the radially inner portion of the conical wall 34. The'forward end of the axial passage 49 communicates with a radial passage 52 which extends outwardly of the rotor and terminates in a discharge opening formed in the circumferential periphery of the rotor. The rotor 46 has an annular bearing flange 53 on the rearward side thereof which is rotatably supported within a substantially annular seat portion 54 formed in the conical wall portion 34. The rotor 46 is thus freely axially slidably mounted on the free end of the motor shaft 26, but is nonrotatably connected to the motor shaft.

The rotor 46 is axially retained on the motor shaft 26 by means of an annular pressure control plate 56 which is disposed closely adjacent but slightly axially spaced from the front axial face of the rotor. The rotor 46 is provided with a small central projection 57 which extends axially forwardly thereof and is disposed for engagement with the'midpoint of the control plate 56 to thus maintain the proper spacing between the control plate and the rotor, while at the same time maintaining the rotor in a proper axial position relative the motor shaft. The pressure control plate 56 has an external diameter which is only slightly smaller than the internal diameter of the annular sidewall portion 36 to result in the formation of a narrow annular clearance space 58 therebetween, which annular clearance space has a small radial width, such as of the order of approximately 0.020 inch. A plurality, here four, of mounting clips or legs 59 are fixedly secured to the outer edge of the control plate 56 and extend axially thereof, which mounting legs 59 are disposedin snug engagement with the annular sidewall portion 36, as by being pressed therein, to fixedly position the control plate 56 relative to the housing and relative to the rotor. The control plate 56, by being slightly axially spaced from the rotor 46, results in the formation of a narrow annular chamber 61 therebetween. Chamber 61 communicates with the flow passageways 48 formed in the rotor by means of the intermediate openings 62 which are formed in the rotor adjacent the radially inner ends of the radial passages 52.

The control plate 56, as illustrated in FIG. 1, is axially positioned between the rotor 46 and the end cover 44, resulting in the formation of an annular fluid pressure chamber 63 between the control plate 56 and the end cover 44. The pressurized fluid discharged from the rotor 46 flows through the annular clearance space 58 (FIG. 5) provided in surrounding relationship to the control plate into the chamber 63 and is then discharged from the pump through a discharge port 64 formed in the end cover 44.

The end cover 44 has a surrounding annular flange 66 extending axially thereof and disposed so as to overlie the seal ring 39. An annular ringlike depression or groove 67 is formed in the cover 44 radially inwardly from the outermost edge thereof resulting in the formation of an annular shoulder 68. The cover 44 is fixedly and securedly connected to the cuplike housing 27 by a plurality of releasable, resilient, L-shaped clips 69 positioned at a plurality of circumferentially spaced locations around the cover. The clips 69 (there being four clips in the illustrated embodiment) are identical and each includes substantially perpendicular leg portions 71 and 72. The leg portion 71 has an offset portion 73 adjacent the free end thereof which is adapted to extend into the ringlike depression 67 to thus overlap the annular shoulder 68 when the leg portion 71 is disposed adjacent the front axial face of the end cover 44. The other leg portion 72 has an arcuate, substantially semicircular hook 74 formed on the free end thereof which overlaps and is interengaged with the hooklike flange 38 formed on the free edge of the housing 27. The clips 69 maintain the cover 44 securely and sealingly connected to the free end of the housing, while at the same time the clips are resiliently deformable to permit the cover to be releasably disconnected from the housing.

Considering now the flow and pressure sensing control device 17, same includes a housing 76 which is positioned directly over or adjacent the upper side of the pump 11. The control housing 76 is, for convenience of manufacture and assembly, constructed of two housing parts 77 and 78 which are fixedly secured, as by screws 79. The front housing part 77 has a pair of rearwardly extending annular projections 81 which extend through a pair of suitable openings formed adjacent the opposite comers of the vertical leg 23 of the mounting bracket 21 for at least partially supporting the control housing relative to the pump.

The control housing 76 has a flow passage extending therethrough which specifically includes a substantially cylindrical inlet chamber 82, an intermediate chamber 83 and a discharge chamber 84. A discharge port 86 communicates with the discharge chamber 84 and is adapted to be connected to any suitable discharge device, such as the discharge line 14.

The front housing part 77 has an enlarged annular portion 87 which projects downwardly in front of the pump so as to radially overlap same, which downwardly projecting portion has an opening 88 fonned therein and disposed in alignment with the discharge port 64 formed in the end cover 44. The annular portion 87 is fixedly connected to the end cover 44 by means of a platelike retainer 89 which is of a substantially U- shaped configuration and has a pair of opposed, resilient legs 91 which have outwardly extending projections adjacent the ends thereof for permitting the legs to fixedly connect the annular portion 87 to the cover 44.

The forward end of the housing part 77 is closed by means of an annular cover 92 which has an annular flange 93 surrounding same and disposed for coaction with a further annular flange 94 which is provided on the housing part 77. The annular flanges 93 and 94 clamp a conventional O-ring seal 96 therebetween. A plurality of resilient clips 97, here three clips, coact between the flanges 93 and 94 for releasably but fixedly securing the cover 92 to the housing part 77. The clips 97, which are received within recesses 98 formed in the front face of the cover 92, are identical to the clips 69 and thus further description of same is not believed necessary.

The cover 92 has a main wall 99 which, as illustrated in FIG. 1, is axially spaced from the annular flange portion 87 to thus result in the formation of a fluid transfer chamber 101 therebetween, which chamber in turn communicates with the inlet chamber 82. The cover 92 also has a substantially cylindrical portion 102 fixedly, here integrally, connected thereto and projecting into the cylindrical inlet chamber 82. The cylindrical portion 102 is of substantially smaller diameter than the chamber 82 to thus result in substantial flow clearance therebetween. The portion 102 has a substantially annular end wall 103 disposed in engagement with an annular wall of the housing part 77, there being a suitable resilient O-ring seal 104 disposed therebetween. The cylindrical projection 102 has a first transverse passage 106 formed therethrough, with a further passage 107 being formed adjacent the rearward end thereof, which passage in turn communicates with a central opening 108 formed in the annular end wall 103.

A one-way check valve 111 is disposed adjacent the end wall 103 for preventing back flow from the intermediate chamber 83 into the inlet chamber 82 through the opening 108. The check valve 111 includes a rigid disk 112 having a pair of parallel flanges disposed for clamping and sealing engagement with the inner edge of an annular seal ring 113. The annular seal ring 113 is mounted on and surrounds the disk 112 and is positioned so that the other annular edge thereof is movable into sealing engagement with the rear surface of the end wall 103 in surrounding relationship to the opening 108 therein. A small flexible strip or flap 114 is integrally connected between the annular seal ring 113 and the O-ring 104 over a small peripheral extent thereof for permitting the check valve 111 to be pivotally moved between closed and opened positions as illustrated respectively by solid and dotted lines in FIG. 1.

The flow of fluid from the intermediate chamber 83 to the discharge chamber 84 is sensed by means of a pressure and flow responsive sensor 116 which includes a substantially cylindrical stem member 117 positioned within the intermediate chamber 83 and having a reduced diameter portion 1 18 formed on the end thereof which projects into the discharge chamber 84. An annular platelike washer member 119 is fixedly mounted on the stem member 117 at the bottom of the reduced diameter portion 118 and is positioned for restricting engagement with a resilient annular seat 121 which is clampingly and sealingly held between the housing parts 77 and 78. Seat 121 has an inwardly directed radial flange constructed of an elastomeric or rubberlike material positioned so as to be sealingly contacted by the outer peripheral portion of the washer 119.

The sensor 116 is slidably movable between open and closed positions due to the reduced end portion 118 being slidably received within an opening 122 formed in an intermediate partition 123 which extends across the discharge chamber 84 and is fixedly secured to the housing part 78. The housing part 77 also has an opening 124 formed therein and substantially aligned with the opening 122 for permitting the forward end of the stem member 117 to be slidably received therein and extend therethrough. A flexible annular diaphragm 126 of conventional construction is sealingly connected between the housing part 77 and the stern member 117 for preventing escape of liquid through the opening 124.

A motor control switch 127 is mounted externally of the control housing 76 and is disposed for actuation by the sensor 116 when same is moved between its open and closed positions. The switch 127 is of conventional construction and includes an actuator button 128 which is spring-urged outwardly of the switch housing to thus normally maintain the switch 127 in an open position. A conventional switchactuating lever 129 is mounted on the switch housing and is disposed to overlie the actuator button 128, with the free end of the actuating lever 129 also being disposed directly adjacent the forward end of the stem member 117. A control spring 131 is positioned to normally resiliently urge the free end of the switch-actuating lever 129 into engagement with the forward end of the cylindrical stem member 1 17.

The control spring 131, in the illustrated emb0di ment, comprises a leaflike spring having a central portion formed with one or more coils which are rotatably supported on a stationary support pin 132. The spring 131 includes a pair of resilient leg portions 133 and 134 extending outwardly from the center coil portion, with the free end of the resilient leg portion 133 being disposed for engagement with the switch-actuating lever 129. The free end of the outer resilient leg portion 134 has a hook 137 formed thereon which is adapted to extend around the free edge of a substantially semicircular stationary flange 136, which flange 136 is fixedly secured to the control housing and has the support pin 132 extending upwardly therefrom. The flange 136 has the upper surface thereof provided with suitable means, such as radial serrations or small upward projections, formed thereon to enable the resilient leg portion 134 to be swingably moved about the support pin 132 into a selected position, with the resilient leg portion 134 thus being held in the selected position due to the serrations or projections which are formed on the upper surface of the flange 136. This thus permits the resilient leg portion 134 to be selectively positioned in either the off position, or in positions which correspond to low, medium" or high pressures, which settings are as indicated in FIG. 6.

OPERATION The operation of the device according to the present invention will be briefly described to insure a more complete understanding thereof.

It will first be assumed that the tank 13 is filled with water, that the system is empty of water, and that the leg portion 134 of the control spring 131 is in its off position. In this off position, the resilient leg 133 exerts little or no force on the switch actuating lever 129 so that the internal switch spring is able to maintain the actuator button 128 in its outward position, whereby the switch 127 is thus open so that the motor 13 is deenergized. After the valve 16 has been opened, the resilient leg portion 134 of the control spring 131 is moved away from its off position, such as by being moved to a medium pressure position as illustrated in FIG. 6. The serrated surface or projections formed on the flange 136 thus hold the leg portion 134 in this selected position. In this position, the resilient leg portion 133 exerts a resilient force on the switch actuating lever 129 which is sufflcient to overcome the springurging of the actuator button 128, thereby causing the button 128 to be depressed inwardly to thus close the switch 127, thereby energizing the motor 13 and causing rotation of the pump rotor 46. This urging of the spring leg portion 133 also causes the sensor 116 to be moved to an open position, as illustrated by the dotted line position of the plate 119 in FIG. 1.

As the pump is operated, water is withdrawn from tank 13 through the inlet port 43 into the supply chamber 42. The water is then drawn through the openings 51 into the passageways 53 whereby, due to centrifugal effects, the water is forced outwardly and discharged adjacent the outer periphery of the rotor. Due to the control plate 56 disposed closely adjacent the front face of the rotor, and due'to the small fins or vanes 141 formed on the front face thereof, the majority of the water discharged from the rotor is prevented from flowing into the narrow chamber 61 provided between the control plate and the rotor. Thus, the discharged water is forced to flow through the small annular clearance space 58 surrounding the control plate 56 into the collection chamber 63. The water then flows through the discharge port 64 into the transfer chamber 101 and from thence into the inlet chamber 82. The water causes the check valve 111 to open so that the water flows into intermediate chamber 83 and past the open sensor 116 into the discharge chamber 84, from which the water flows into and through the delivery line 14 and through the open valve 16 so as to be supplied to a suitable discharge point, such as by being discharged from a manually actuated faucet. The pump 11 and motor 12 will be continuously energized so long as the valve 16 is open, thereby permitting a continuous pumping of water through the pump and through the delivery line 14.

When the valve 16 is closed, the water within the control device 17 is trapped and further operation of the pump 1 1 causes the pressure of the water to rapidly increase. While the pressure of the water within the intermediate chamber 83 and discharge chamber 84 is substantially the same, nevertheless the area of the plate 119 on the downstream side thereof issubstantially greater than the area of the plate 119 on the upstream side thereof. This thus results in the pressurized fluid imposing an unbalanced force on the sensor 116 which moves same forwardly (leftwardly in FIG. 1) so that the plate 119 is thus moved into restricting engagement with the seat 121, thereby isolating the discharge chamber 84 from the intermediate chamber 83. This leftward movement of the sensor 116 also causes the cylindrical stem member 1 17 to be extended outwardly of the housing and causes the switch-actuating lever 129 to be pivoted outwardly in opposition to the urging of the resilient leg portion 133, whereby the internal switch spring causes the actuator button 128 to be moved outwardly to thus open the switch 127. Opening of the switch 127 thus de-energizes the motor 12 and stops the pump 11. When the pump 11 is stopped, any tendency of the water trapped within the control system on the downstream side of the check valve l11'is prevented due to a movement of the check valve into its closed position, as illustrated by solid lines in FIG. 1.

After the motor-pump unit has been stopped, a predetermined quantity of water is still contained within the inlet chamber 82 and the transfer chamber 101. Since these chambers are disposed at an elevation above the pump rotor, the fluid within the chambers thus flows backwardly into the pump rotor so as to thus self-prime the pump in order to permit effecient starting of the pump upon further energization thereof.

When the liquid supply system is further utilized, such as by opening of the valve 16, the pressure of the fluid trapped within the discharge chamber 84 immediately decreases whereupon the fluid within the intermediate chamber 83 and the urging of the springlike leg portion 133 causes the sensor 116 to again be moved rearwardly (rightwardly in FIG. 1) into its closed position, whereupon the switch 127 will thus close to again re-energize motor 12 to accordinglycause activation of the pump 11. Water will again be supplied from the pump through the control device 17 into the delivery line 14 so long as the valve 16 remains open. The device of the present invention thus relates in the motor and pump being automatically energized and deenergized in response to the external demand of water.

Considering briefly the effect of the control spring 131, it will be appreciated that the spring 131 can be adjusted to impose a selectively variable force on the end of the stem member 117 for urging the sensor 116 toward its open position. For example, when the spring 131 is moved into the medium pressure position, a predeterminedresilient force will be imposed on the end of the cylindrical stem member 117 tending to urge same rearwardly (rightwardly in FIG. 1). On the other hand, if the leg portion 134 of the spring 131 is moved into the high" pressure position, a substantially larger force will be imposed on the forward end of the stem member 117 tending to urge same into its open posi tion. Accordingly, the restoring force developed by the pressurized fluid within the chambers 83 and 84 must accordingly increase in proportion to the urging of the force developed by the spring 131 in order to permit the sensor 116 to be returned to its closed position. When the control spring is in its medium position, the water within chambers 83 and 84 will be able to return the sensor 116 to its closed position upon reaching a first predetermined maximum pressure. On the other hand, when the control spring is in its high pressure position, the water within the chambers 83 and 84 must reach a second predetermined maximum pressure which is substantially greater than the first predetermined maximum pressure in order to develop sufficient restoring force to return the sensor 1 16 to its closed po sition. Thus, by suitably selecting the setting of the control spring 131, the sensitivity of the motor pump unit (that is, the automatic energization and deenergization thereof) to the external demand for water can thus be selectively varied.

In the event that the water contained within the pump 11, particularly the water within the collection chamber 63, should freeze, the expansion caused by the freezing of the water would result in application of a substantial internal force on the end cover 44. When this force reaches a predetermined magnitude, the releasable clips 69 will tend to pivot around the free end of the arcuate hook portions 74 at the point where same engage the radial hook portion 38. Also, the leg portions 71 will resiliently deform relatively to the leg portions 72, whereupon one or more of the clips 69 will resiliently snap outwardly to disengage the cover 44, thereby causing the cover to be partially or totally disconnected from the housing 27. The expansion as caused by the freezing of the water thus causes little or no damage to the pump structure.

The structure and operation described above relate to use of the pump 11 in combination with the flow control device 17. However, if desired, the control device 17 can be removed from the pump 11, and the pump 11 can have a nozzle 141(FlG. 8) mounted on the discharge part 64.

Although a particular preferred embodiment of the invention has been disclosed in detail for illustrative purposes, it will be recognized that variations or modifications of the disclosed apparatus, including the rearrangement of parts, lie within the scope of the present invention.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a liquid supply system having a supply tank, at least one outlet valve, a pump connected between the supply tank and the outlet valve, the pump having an inlet in communication with the tank, a motor drivingly connected to the pump, and a flow and pressure sensing control device connected in series between the discharge of the pump and the outlet valve for automatically energizing and de-energizing said motor in response to the demand for liquid through said control device, comprising the improvement wherein:

said pump includes housing means and a pump rotor rotatably supported relative to said housing means, said housing means including wall means defining a chamber in which is positioned said pump rotor, said chamber being open at one end thereof, said housing means also including separable end wall means positioned adjacent said first-mentioned wall means for closing the one end of said chamber, coupling means coacting between said firstmentioned wall means and said end wall means for fixedly but releasably connecting same to close said one end of said chamber, said coupling means being automatically releasable upon development of a predetermined force within said chamber as imposed on said end wall means for permitting at least a portion of said end wall means to be moved away from said first-mentioned wall means to at least partially'uncover said one end of said chamher, and a substantially imperforate control plate positioned closely adjacent an axial end face of said rotor, said control plate being substantially coextensive with said axial end face of said rotor and disposed axially between said rotor and said end wall means, said control plate being spaced from said end wall means to define a liquid collection chamber therebetween, at least a portion of the periphery of said control plate being spaced from the inner periphery of said first-mentioned wall means to define a narrow clearance space therebetween for permitting liquid discharged from said rotor to flow through said narrow clearance space directly into said collection chamber.

2. A system according to claim 1, wherein said firstmentioned wall means includes a platelike wall member positioned closely adjacent and substantially coextensive with the other axial end face of said rotor, and an annular supply chamber formed within said pump housing means and positioned directly adjacent said platelike wall member, said rotor being constructed of a plastic material and having a plurality of flow passages extending radially thereof with the outer ends of said flow passages terminating adjacent the outer periphery of the rotor and the inner ends of said flow passages terminating adjacent the center of the rotor and communicating with said annular supply chamber.

3.- A system according to claim 2, wherein said coupling means includes a plurality of releasable resilient clips coacting between said end wall means and said first-mentioned wall means at a plurality of annularly spaced locations positioned in surrounding relationship to the rotor.

4. A pump and motor assembly including a centrifugal pump having housing means defining an internal chamber and a pump rotor rotatably disposed within said internal chamber, and motor means drivingly connected to said rotor for permitting rotation of same, said rotor having a plurality of flow passages extending radially thereof, with the inlet ends of said flow passages being disposed adjacent the center portion of said rotor and the outlet ends of said flow passages being disposed adjacent the outer periphery of said rotor, comprising the improvement wherein:

said housing means including first and second end walls positioned on opposite axial sides of said rotor and a peripheral sleevelike wall extending between the outer edges of said end walls in surrounding relationship to and spaced from the periphery of said rotor, said first end wall being positioned closely adjacent but slightly axially spaced from the adjacent axial face of said rotor, said rotor having an annular bearing portion rotatably supported on said first end wall, said first end wall further having opening means therethrough adjacent the center portion of said rotor and communicating with the inlet ends of said flow passages for permitting liquid to be supplied thereto, the other end wall being axially spaced a substantial distance from the other axial face of said rotor, a substantially annular flow control plate stationarily positioned closely adjacent but slightly spaced from said other axial end face of said rotor, said flow control plate being substantially imperforate and substantially coextensive with the other axial end face of said rotor, said flow control plate being disposed axially between the rotor and said other end wall and being spaced from said other end wall to define a liquid collection chamber therebetween, at least a portion of the outer periphery of said flow control plate being slightly spaced from said peripheral sleevelike wall to define a narrow flow clearance space therebetween for permitting liquid discharged from said rotor to flow through said clearance space into said collection chamber, whereby said control plate prevents the pressurized water discharged from the said rotor from imposing a large unbalanced axial force on said rotor, and said housing means including a discharge port formed therein and communicating with said collection chamber.

5. An assembly to claim 4, wherein said flow control plate has a plurality of substantially perpendicularly extending legs secured thereto adjacent the periphery thereof at a plurality of circumferentially spaced locations, said legs being fixedly engaged with the inner periphery of said peripheral sleevelike wall for maintaining said control plate stationarily positioned concentrically within said peripheral wall, said control plate having an outer diameter slightly less than the inner peripheral diameter of said peripheral wall for defining a narrow annular clearance space therebetween.

6. An assembly according to claim 4, wherein said other end wall is separable from said peripheral wall, said other end wall and said peripheral wall each having annular flange portions positionable adjacent one another, and releasable coupling means coacting between said flange portions for fixedly but releasably maintaining said other end wall in closed sealing engagement with said peripheral wall, said releasable coupling 13 U means including means for permitting said other end wall to at least partially automatically separate from said peripheral wall upon the occurrence of a predetermined pressure within said collection chamber.

7. An assembly according to claim 6, wherein said releasable coupling means includes a plurality of resilient releasable clips coacting between said flange portions.

8. In a water supply system having a supply tank, at least one outlet valve, a pump connected between the supply tank and the outlet valve, the pump having an inlet in communication with the tank, a motor drivingly connected to the pump, and a flow and pressure sensing control device connected in series between the discharge of the pump and the outlet valve for automatically energizing and de-energizing said motor in response to the demand for water through said control device, comprising the improvement wherein:

said pump includes housing means and a pump rotor rotatably supported relative to said housing means, said housing means including wall means defining a chamber in which is positioned said pump rotor, said chamber being open at one end thereof, said housing means also including a separable end wall positioned adjacent said wall means for closing the one end of said chamber, said end wall having an outlet opening fomied therein for permitting discharge of water from said chamber, coupling means coacting between said wall means and said end wall (1) for fixedly but releasably connecting same to close said one end of said chamber and (2) for permitting said end wall to at least partially automatically separate from said wall means due to freezing of the water contained within said chamber, said wall means and said end wall each having annular flanges disposed adjacent one another, and said coupling means including a plurality of resilient releasable clips coacting between said flanges at a plurality of circumferentially spaced locations, each of said clips includes a pair of substantially perpendicular resilient leg portions having their adjacent ends fixedly connected together, one of said clips being provided with an arcuate hook adjacent the free end thereof, the other of said leg portions being provided with a transversely projecting portion adjacent the free end thereof.

9. A system according to claim 8, wherein said flow and pressure sensing control device includes a housing member positioned above said housing means and defining therein a priming compartment for collecting a supply of water capable of priming said pump, said housing member including a portion thereof disposed in sealed relationship with the outlet opening formed in said end wall whereby the water as discharged from said chamber is supplied to said priming compartment. 

1. In a liquid supply system having a supply tank, at least one outlet valve, a pump connected between the supply tank and the outlet valve, the pump having an inlet in communication with the tank, a motor drivingly connected to the pump, and a flow and pressure sensing control device connected in series between the discharge of the pump and the outlet valve for automatically energizing and de-energizing said motor in response to the demand for liquid through said control device, comprising the improvement wherein: said pump includes housing means and a pump rotor rotatably supported relative to said housing means, said housing means including wall means defining a chamber in which is positioned said pump rotor, said chamber being open at one end thereof, said housing means also including separable end wall means positioned adjacent said first-mentioned wall means for closing the one end of said chamber, coupling means coacting between said first-mentioned wall means and said end wall means for fixedly but releasably connecting same to close said one end of said chamber, said coupling means being automatically releasable upon development of a predetermined force within said chamber as imposed on said end wall means for permitting at least a portion of said end wall means to be moved away from said first-mentioned wall means to at least partially uncover said one end of said chamber, and a substantially imperforate control plate positioned closely adjacent an axial end face of said rotor, said control plate being substantially coextensive with said axial end face of said rotor and disposed axially between said rotor and said end wall means, said control plate being spaced from said end wall means to define a liquid collection chamber therebetween, at least a portion of the periphery of said control plate being spaced from the inner periphery of said first-mentioned wall means to define a narrow clearance space therebetween for permitting liquid discharged from said rotor to flow through said narrow clearance space directly into said collection chamber.
 2. A system according to claim 1, wherein said firstmentioned wall means includes a platelike wall member positioned closely adjacent and substantially coextensive with the other axial end face of said rotor, and an annular supply chamber formed within said pump housing means and positioned directly adjacent said platelike wall member, said rotor being constructed of a plastic material and having a plurality of flow passages extending radially thereof with the outer ends of said flow passages terminating adjacent the outer periphery of the rotor and the inner ends of said flow passages terminating adjacent the center of the rotor and communicating with said annular supply chamber.
 3. A system according to claim 2, wherein said coupling means includes a plurality of releasable resilient clips coacting between said end wall means and said first-mentioned wall means at a plurality of annularly spaced locations positioned in surrounding relationship to the rotor.
 4. A pump and motor assembly including a centrifugal pump having housing means defining an internal chamber and a pump rotor rotatably disposed within said internal chamber, and motor means drivingly connected to said rotor for permitting rotation of same, said rotor having a plurality of flow passages extending radially thereof, with the inlet ends of said flow passages being disposed adjacent the center portion of said rotor and the outlet ends of said flow passages being disposed adjacent the outer periphery of said rotor, comprising the improvement wherein: said housing means including first and second end walls positioned on opposite axial sides of said rotor and a peripheral sleevelike wall extending between the oUter edges of said end walls in surrounding relationship to and spaced from the periphery of said rotor, said first end wall being positioned closely adjacent but slightly axially spaced from the adjacent axial face of said rotor, said rotor having an annular bearing portion rotatably supported on said first end wall, said first end wall further having opening means therethrough adjacent the center portion of said rotor and communicating with the inlet ends of said flow passages for permitting liquid to be supplied thereto, the other end wall being axially spaced a substantial distance from the other axial face of said rotor, a substantially annular flow control plate stationarily positioned closely adjacent but slightly spaced from said other axial end face of said rotor, said flow control plate being substantially imperforate and substantially coextensive with the other axial end face of said rotor, said flow control plate being disposed axially between the rotor and said other end wall and being spaced from said other end wall to define a liquid collection chamber therebetween, at least a portion of the outer periphery of said flow control plate being slightly spaced from said peripheral sleevelike wall to define a narrow flow clearance space therebetween for permitting liquid discharged from said rotor to flow through said clearance space into said collection chamber, whereby said control plate prevents the pressurized water discharged from the said rotor from imposing a large unbalanced axial force on said rotor, and said housing means including a discharge port formed therein and communicating with said collection chamber.
 5. An assembly to claim 4, wherein said flow control plate has a plurality of substantially perpendicularly extending legs secured thereto adjacent the periphery thereof at a plurality of circumferentially spaced locations, said legs being fixedly engaged with the inner periphery of said peripheral sleevelike wall for maintaining said control plate stationarily positioned concentrically within said peripheral wall, said control plate having an outer diameter slightly less than the inner peripheral diameter of said peripheral wall for defining a narrow annular clearance space therebetween.
 6. An assembly according to claim 4, wherein said other end wall is separable from said peripheral wall, said other end wall and said peripheral wall each having annular flange portions positionable adjacent one another, and releasable coupling means coacting between said flange portions for fixedly but releasably maintaining said other end wall in closed sealing engagement with said peripheral wall, said releasable coupling means including means for permitting said other end wall to at least partially automatically separate from said peripheral wall upon the occurrence of a predetermined pressure within said collection chamber.
 7. An assembly according to claim 6, wherein said releasable coupling means includes a plurality of resilient releasable clips coacting between said flange portions.
 8. In a water supply system having a supply tank, at least one outlet valve, a pump connected between the supply tank and the outlet valve, the pump having an inlet in communication with the tank, a motor drivingly connected to the pump, and a flow and pressure sensing control device connected in series between the discharge of the pump and the outlet valve for automatically energizing and de-energizing said motor in response to the demand for water through said control device, comprising the improvement wherein: said pump includes housing means and a pump rotor rotatably supported relative to said housing means, said housing means including wall means defining a chamber in which is positioned said pump rotor, said chamber being open at one end thereof, said housing means also including a separable end wall positioned adjacent said wall means for closing the one end of said chamber, said end wall having an outlet opening formed therein for permitting discHarge of water from said chamber, coupling means coacting between said wall means and said end wall (1) for fixedly but releasably connecting same to close said one end of said chamber and (2) for permitting said end wall to at least partially automatically separate from said wall means due to freezing of the water contained within said chamber, said wall means and said end wall each having annular flanges disposed adjacent one another, and said coupling means including a plurality of resilient releasable clips coacting between said flanges at a plurality of circumferentially spaced locations, each of said clips includes a pair of substantially perpendicular resilient leg portions having their adjacent ends fixedly connected together, one of said clips being provided with an arcuate hook adjacent the free end thereof, the other of said leg portions being provided with a transversely projecting portion adjacent the free end thereof.
 9. A system according to claim 8, wherein said flow and pressure sensing control device includes a housing member positioned above said housing means and defining therein a priming compartment for collecting a supply of water capable of priming said pump, said housing member including a portion thereof disposed in sealed relationship with the outlet opening formed in said end wall whereby the water as discharged from said chamber is supplied to said priming compartment. 